1. Technical Field
The present invention is directed toward window sash locks and more particularly toward easily assembled low profile window sash locks.
2. Background Art
Window locks are known in the art that generally involve having a catch with a handle operator affixed to a window frame which interacts with a keeper on a corresponding section of a movable window sash to securely hold the sash tightly against the frame. Also known in the art are devices for sequential multipoint lock-up of the movable window sash with the window frame. These latter devices are locks which have a handle actuator interacting with a keeper at one point on a window frame and sash respectively which causes a second lock to engage a keeper at a distant location.
Commonly owned U.S. patent application Ser. No. 297,490 in the name of Nolte et al filed Jan. 17, 1989 now abandoned, hereby incorporated by reference, discloses such a multipoint lock for a window sash. This device uses a slider connecting two spaced apart catches which can interact with keepers affixed to a window sash to establish a locked condition of the window. The movement of a handle actuator from its unlocked position causes an adjacent cam member on a catch to connect with a planar portion of an associated ramped keeper. The movement of the catch causes the slider, which has a length of movement along a path between the two keepers, to move the second cam member onto the planar section of the associated ramped keeper.
However, with many such window locks, there is a danger of the handle portion being brushed against or otherwise moved, resulting in the accidental unlocking of the window. Likewise, there is a danger of the handle being broken off or otherwise disabled.
Further, there is a problem in maintaining a handle, which is rotated in an arc between a locked and unlocked position, in a limit position. For example, when such a lock is affixed vertically on a window frame, gravitational forces act on the lock handle while in the raised position to push it downward. Therefore, it is desirable to maintain the handle in its locked or unlocked position in opposition to forces moving it between limit positions.
The present invention is directed toward overcoming one or more of the problems discussed above.